Method and apparatus for dispensing pellets into lamps

ABSTRACT

Lamp-dosing material such as indium triiodide is drawn, in molten form, into tubing of slippery plastic material such as Teflon, and allowed to solidify. A length of the tubing and its contents is placed into an elongated opening in a metal dispenser block. The dispenser block is heated to cause the plastic tubing to expand, and a plunger forces a measured length of dosing material out of the tubing. A cutter blade slices off the exposed length of material whereupon it falls into a lamp bulb which has been inserted into an opening in the dispenser block. An inert gas is flowed through the interior of the dispensing block to protect the dosing material from moisture in the atmosphere.

United States Patent 11 1 1111 3,729,247 Schaller 5] Apr. 24, 1973 4] METHOD AND APPARATUS FOR 3,348,588 10/1967 Ayotte ..316/30 DISPENSING PELLETS INTO LAMPS 3,584,359 6/l97l Werner et al ..29/25.l l [75] Inventor: Da 'id R. Schaller, Chagrin Falls, Primary Examiner Loweu Larson Ohlo Attorney-Norman C. Fulmer et al.' [73] Assignee: General Electric Company, Schenectady, NY. ABSTRACT [22] Filed: 19, 1971 Lamp-dosing material such as indium triiodide is drawn, in molten form, Into tubing of slippery plastic [21] Appl. No.2 200,325 material such as Teflon, and allowed to solidify. A length of the tubing and its contents is placed into an 521 U.S.Cl ..3l6/l6,3I6/3() lf f m"? f" f The S l 1 Cl "01 9 m dispenser block is heated to cause the plastic tubing to I J a I expand, and a plunger forces a measured length of [58] held 0 Search ..3l6/3, 16,251), dosing material Om Ofthc tubing A Cutter blade Slices oil the exposed length of material whereupon it falls into a lamp bulb which has been inserted into an [56] References C'ted opening in the dispenser block. An inert gas is flowed UNITED STATES PATENTS through the Inter orof the d spens ng block to protect the dosmg material from molsture 1n the atmosphere. l.585,803 5/1926 Van Voorhis -3l6/3 1,817,445 8 1931 Robinson 9 ClaIm-S, 3 Drawlng Figures 3,328,l08 6/1967 Keenan et al ..3 l 6/30 '1 I. I; I; .llllllllllllllllllllllllllll l [I l l 5 VI I. 'a-Wwlmug Patented April 24, 1973 I Invenior David R. SchaLLeT b8] We. $105M.-

I-Iis A t torneg METHOD AND APPARATUS FOR DISPENSING PELLETS INTO LAMPS CROSS-REFERENCE TO RELATED APPLICATION US. Pat. application Ser. No. 72,051, Stephen P. Senft, filed Sept. 14, 1970, Method of Dosing Lamps, assigned to the same assignee as the present invention.

BACKGROUND OF THE INVENTION lamps with pellets of suitable material to provide the gas fill. Such a gas fill causes a regenerative cycling action which prevents evaporated electrode material (in an arc lamp) or filament material (in a filament lamp) from depositing on the bulb and causing blackening.

US. Pat. No. 3,305,289 to Elmer G. Fridrich, assigned to the same assignee as the present invention, describes a method which has been used for providing a gas fill in lamps, in which an inert gas is fed over heated iodine crystals so as to pick up iodine vapor. The vaporcarrying inert gas is then fed into the lamp bulb which is chilled to cause condensation of the iodine vapor.

The above-referenced patent application describes a method of dosing lamps, wherein a dosing material such as indium triiodide, in molten form, is drawn into tubing of slippery plastic material such as Teflon, and allowed to solidify. The tubing and its contents are sliced at suitable intervals for providing desired quantities of dosage material per lamp, and the pellets of dosage material are forced out of the sliced tubing sections and into the lamp bulbs.

SUMMARY OF THE INVENTION Objects of the invention are to provide an improved method and apparatus for manufacturing gas-filled lamps, and to provide an improved method and apparatus for dosing lamps with pellets of dosing material.

The method of the invention comprises, briefly and in a preferred embodiment, the steps of drawing dosing material, in molten form, into tubing of slippery plastic material, allowing the dosing material to solidify, heating a length of the plastic tubing and its contents to expand the tubing, extruding a desired length of the dosing material out of the tubing, slicing off the exposed extruded length of dosing material, and placing the sliced-off length of dosing material into a lamp bulb. The apparatus of the invention comprises, briefly and in a preferred embodiment, a metal dispenser block provided with an elongated opening for containing a length of plastic tubing filled with dosing material, a shoulder being provided at an end of the elongated opening for restraining the plastic tubing from axial movement, means for heating the dispenser block to expand the plastic tubing, plunger means for extruding a desired length of the dosing material from the plastic tubing at the shoulder end of the elongated opening, and cutter means for slicing off the extruded dosing material. The apparatus also preferably includesan opening for receiving a portion of a lamp bulb into which the sliced-off piece of dosing material is to be inserted, and means for flowing an inert gas through the openings of the block.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a pellet dispensing apparatus in accordance with a preferred embodiment of the invention;

FIG. 2 is a crosssectional view taken on the line 2- 2 of FIG. 1, prior to ejecting and slicing a length of dosing material; and

FIG. 3 is a view similar to FIG. 2, but immediately after a length'of dosing material has been extruded and sliced.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawing, the preferred embodiment of the invention comprises a dispensing block 11 preferably made of metal such as aluminum. An electrical heater member 12 is positioned in an opening in the block 11, so as to heat the block 11 for reasons to be described. An elongated opening 13 is provided into the block 11 from the upper surface thereof, and the upper portion of the opening 13 is threaded to receive a threaded plunger member 15 comprising a threaded portion 16, an elongated plunger rod 17 extending axially from an end of the threaded portion 16, and a turning means 17 and turning indicator pointer 18 at the other end thereof. The threaded portion 16 is adapted to screw into the threaded upper portion of the opening 13, so that the plunger 17 will force or extrude a dosing material 21 out of an end of a plastic tubing 22 which contains a core of the dosing material 21. A shoulder 23 is provided at the lower end of the elongated opening 13, for restraining axial movement of the tubing 22, the shoulder 23 being such that the extruded core of dosing material 21 can pass therethrough; A circular dial scale 26 is provided on the upper surface of the dosing block 11, so that the turning means 17 can be turned, either manually or by means of machinery, a desired amount, as indicated by the indicating pointer 18 in conjunction with the dial scale 26, to extrude a desired length of the dosing material 21 out of the bottom end of the plastic tubing 22.

A cutter blade 27, preferably made from resilient metal, is attached to the exterior of the dosing block 11 by screws 28 or other suitable means, and is adapted to extend away from the surface of the dosing block 11, and is bent at 29 so that the end portion thereof extends through a suitable slot opening 30 in the block 11 located so as to communicate with the lower end of the plastic tubing 22 at the shoulder 23. The inner end of the cutter member 27 is beveled to provide a sharp edge for slicing the dosing material 21. To facilitate making the cutter blade slot 30 in the block 11, the block 11 is made in two parts, one part 31 being provided with the cutter blade slot 30 on the upper surface thereof, the part 31 being attached to the main portion of the block 1 l by means of screws 32 or other suitable means, and abutting thereagainst along the line 33. By this arrangement, the shoulder 23 supports only a portion of the lower end of the plastic tubing 22, whereby the cutter blade 27 can slide across the lower end of the tubing immediately adjacent thereto.

An elongated opening 36 is provided into the block 11 at the bottom thereofdin axial alignment with the elongated opening 13, and in communication therewith via the shoulder 23. The opening 36 is adapted to receive a tubular end portion 37 of a lamp bulb 38 in a position such that when a length of the dosing material 21 is sliced off, as will be described, it will fall into the bulb 38.

Hose and tubing means 41 are attached to or extend within the block 11, to communicate with one or both of the elongated openings 13 and 36, so as to flush these openings with an inert gas such as nitrogen, fed into the hose and tubing means as indicated by the arrow 42, for the purpose of protecting the dosing material 21 from moisture in the atmosphere.

The apparatus described above is utilized as follows in carrying out the method of the invention. The dosing material 21 may be provided in the plastic tubing 22 by suitable means, such as that described in the abovereferenced patent application, by placing an end of tubing 22 into molten dosing material such as indium triiodide, and applying vacuum at the other end of the tubing to draw the molten dosing material into the tubing 22, whereupon the material 22 is allowed to cool and solidify. Preferably, a substantial length of Teflon tubing is thus filled with the dosing material. Then, a suitable length of the plastic tubing, containing the dosing material, is cut off, for example a length of one or two inches, which is then inserted into the lower portion of the elongated opening 13 as shown in the drawing. The extruding plunger means 15 is then screwed into position. Meanwhile, the block 11 has been heated to suitable temperature by means of the heater 12, which may be a SO-Watt heater element, so as to heat the block 11 sufficiently to cause the length of plastic tubing 22 to expand sufficiently to permit the ejector rod 17 to extrude the dosing material 21 from the tubing 22. The tubing 22 expands more than the core 21 when heated. The extruding means 15 is then turned a sufficient amount so that the plunger 17 ejects a desired length of dosing material 21 out of the bottom end of the plastic tubing 22, whereupon the cutter means 27 is pushed, either manually or by machinery, so that the cutting edge thereof slices off the extruded exposed end of dosing material which then falls into the lamp bulb 38 as indicated by numeral 46 in FIG. 3. The flow of inert gas through the interior of the block 11, particularly in the elongated opening 13 and 36, protects the dosing material from atmospheric moisture, thus insuring a clean, dry, pure pellet 46 of dosing material being ejected into the lamp bulb 38 by the dosing block apparatus 11.

As will be apparent from the foregoing description, the invention insures the dosing of lamp bulbs with clean, pure and dry dosing material, since only the ends of the dosing material are exposed while in the tubing 22, and the pellets of dosing material are ejected into the lamp bulbs 38 immediately upon being extruded and sliced. The invention also achieves fast and economical dosing of lamps, and provides for immediate changes in the length, and hence size, ofthe extruded pellets, so as to readily accommodate for changes in bulb size. These features are improvements over the previous method of slicing the tubing and then transporting the slice of tubing into position for extrudingi tscore into a lamp bulb.

hile a preferred embodiment of the invention has been shown and described, other embodiments and modifications thereof will become apparent to persons skilled in the art, and will fall within the scope ofinvention as defined in the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A method of dosing lamps with pellets of dosing material, comprising the steps of heating a length of plastic tubing containing a core of dosing material to a temperature sufficient to expand the tubing, extruding a desired length of said core from an end of the tubing, slicing off the extruded length of core to provide a pellet, and placing said pellet into a lamp bulb.

2. A method as claimed in claim 1, in which the step of placing the pellet into the lamp bulb comprises positioning the lamp bulb beneath the extruded length of core and permitting the sliced-off pellet to fall into the lamp bulb immediately following said slicing step.

3. A method as claimed in claim 2, including the step of flowing an inert gas in the region of said extruded length of core and the path of said falling of the pellet into the lamp bulb.

4. A method as claimed in claim 3, in which said dosing material comprises indium triiodide.

5. Apparatus for dosing lamps with pellets of dosing material, comprising a dispenser block provided with an elongated opening adapted to receive a length of plastic tubing containing a core of dosing material, shoulder means at an end of said elongated opening for restraining said plastic tubing from axial movement, means for heating said dispenser block to a temperature sufficient to expand said tubing, plunger means for extruding said core of dosing materiala desired length from the end of said tubing at said shoulder means, and cutter means for slicing off a desired length of the extruded core to provide a pellet of dosing material.

6. Apparatus as claimed in claim 5, in which said cutter means comprises a cutting blade arranged to move transversely across and closely adjacent to said end of the tubing at said shoulder means.

7. Apparatus as claimed in claim 5, including means for positioning a lamp bulb below said extruded length of core whereby said pellet will fall into said lamp bulb immediately following said slicing of the core to provide the pellet.

8. Apparatus as claimed in claim 7, in which said elongated opening extends vertically into said dispenser block from the top thereof, and in which said means for positioning a lamp bulb comprises an opening into said dispenser block from the bottom thereof substantially in axial alignment with said elongated opening and adapted to receive and position at least a portion of said lamp bulb.

9. Apparatus as claimed in claim 8, including means for flowing an inert gas in said dispenser block in the region of said extruded length of core and the path of said falling of the pellet into the lamp bulb. 

2. A method as claimed in claim 1, in which the step of placing the pellet into the lamp bulb comprises positioning the lamp bulb beneath the extruded length of core and permitting the sliced-off pellet to fall into tHe lamp bulb immediately following said slicing step.
 3. A method as claimed in claim 2, including the step of flowing an inert gas in the region of said extruded length of core and the path of said falling of the pellet into the lamp bulb.
 4. A method as claimed in claim 3, in which said dosing material comprises indium triiodide.
 5. Apparatus for dosing lamps with pellets of dosing material, comprising a dispenser block provided with an elongated opening adapted to receive a length of plastic tubing containing a core of dosing material, shoulder means at an end of said elongated opening for restraining said plastic tubing from axial movement, means for heating said dispenser block to a temperature sufficient to expand said tubing, plunger means for extruding said core of dosing material a desired length from the end of said tubing at said shoulder means, and cutter means for slicing off a desired length of the extruded core to provide a pellet of dosing material.
 6. Apparatus as claimed in claim 5, in which said cutter means comprises a cutting blade arranged to move transversely across and closely adjacent to said end of the tubing at said shoulder means.
 7. Apparatus as claimed in claim 5, including means for positioning a lamp bulb below said extruded length of core whereby said pellet will fall into said lamp bulb immediately following said slicing of the core to provide the pellet.
 8. Apparatus as claimed in claim 7, in which said elongated opening extends vertically into said dispenser block from the top thereof, and in which said means for positioning a lamp bulb comprises an opening into said dispenser block from the bottom thereof substantially in axial alignment with said elongated opening and adapted to receive and position at least a portion of said lamp bulb.
 9. Apparatus as claimed in claim 8, including means for flowing an inert gas in said dispenser block in the region of said extruded length of core and the path of said falling of the pellet into the lamp bulb. 